I obviously don't have an EFI partition because, as I stated, I am on a legacy bios. I do have a Dell partition with the flag diag on sda1. My first,sda, internal, spinning hard drive, has Windows 7 on it . My secondary, New SSD drive has Linux Mint 18.2 on it, sdb. sdb1 is where the linux boot partition is, 250mb. sdb2 is root, 224gb and sdb3 is the swap partition.
Forgive me, but I don't get why you consider this hijacking this thread when we both have SSD's, Dell systems and have solved our issue by creating a separate boot partition. Is it because he is UEFI and I am on legacy bios, with an msdos partition table? It appears that there are more things here similar than different, as to be relevant.
One of my mistakes may have been that I originally installed Linux Mint with the SSD drive connected to an external SATA to USB adapter. That first install is what resulted in booting to the grub rescue menu, Maybe that is why it only worked with a separate boot parition? This original install to sdf,sdf1 with the boot flag, sdf2 for root, still shows up in the /etc/fstab file. When I moved it to the internal SATA connector, it booted up just fine,as far as I can tell. I resized my partitions later to add the swap partition, which was sdf3. Currently they are sdb1, sdb2 and sdb3. I only later added the swap partition to try to solve the suspend problem when using the external SATA to USB adapter. Suspend now works great when connected internally.
My assumption is that the swap partition is not really needed with the SSD, as I rarely ever see it used when looking at it in system monitor. Right now it is using 8.5mb, the most I have ever seen, after several days running without rebooting. That seems to maybe be a memory leak. After a fresh boot it shows 0 swap for some time. I attribute the increase in swap to Firefox with many tabs open over several days. When I installed Linux Mint I chose other, fearing that if I didn't, it would overwrite my Windows 7 installed on sda, or mess up its booting, with the default Mint install options.
From my /etc/fstab:
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sdf2 during installation
UUID=02d659d3-207b-45e3-ae52-b1c1a144f749 / ext4 noatime,errors=remount-ro 0 1
# /boot was on /dev/sdf1 during installation
UUID=ec1d3a07-0903-47e0-8450-35de5b4f3df2 /boot ext4 noatime,defaults 0 2
UUID=c03fc742-b4f0-4a20-aa18-92998b7d84ec none swap sw,pri=-1 0 0
With all of this added info maybe I have now hijacked this thread, so I apologize.